Bending machine



lNOV-7, 1967 y R. E. sMn'H, .1R 3,350,912

` r BENDING MACHINE Filed May 2l, 1965 5 Sheets-Sheet l Nov. 7, 1967 R. E. SMITH, .1R

BENDING MACHINE File May 21, 1965 5 Sheets-Sheet 2 Hrr mll .lbf

NOV- 7, 1967 R,E.SM1TH,JR V3,350,912

BENDING MACHINE Filed may 21, 1965 5 sheets-sheet 3 NOV. 7, 1967 R E, SMlTH, JR I 3,350,912

BENDING MACHINE Filed May 21, 1965 5 Sheets-Sheet 4 fm ,fz/7 m@ j@ Z/ l W- IUI r wa;

Z/ t) -fa @i i? Nov. 7, 1967 l R. E. SMITH, .1R 3,350,912 A BENDING MACHINE Filed May 21, 1965 v 5 sheets-sheet United States Patent Gtice 3,350,912 Patented Nov. 7, 1967 3,350,912 BENDING MACHINE Raymond E. Smith, Jr., 385 Greenwood Ave., Lake Forest, Ill. 60045 Filed May 21, 1965, Ser. No. 457,761 Claims. (Cl. 72-310) ABSTRACT OF THE DISCLOSURE A cleat bending machine in which the bending platen rotates through more than 180 degrees and a cooperating blade is automatically retracted after less than 180 degrees of rotation so that a cleat is formed with a bend exceeding 180 degrees. The bending platen, and cooperating blade, are rotated through bending travel in one continuous movement by a hydraulic power system controlled through valve means by the operator.

This invention relates in general to bending sheet metal or the like. It deals more particularly with a machine for bending sheet metal for forming an edge fold or cleat thereon.

It is an object of the present invention to provide a new concept in cleat bending.

It is another object to provide a new and improved cleat bending machine.

It is still another object to provide a cleat bending machine which effects a bend in excess of 180 to assure positive interlock between duct sections, for example.

It is yet another object to provide a cleat bending machine which effects a bend in excess of 180 in one continuous bending operation.

It is a further objective to provide a cleat bending machine of the aforedescribed character wherein an entire cleat forming cycle requires a minimal amount of time.

It is yet a further object to provide a cleat bending machine which effects a repetitively uniform bending operation with a hydraulic power system.

It is yet a further object to provide a cleat bending machine which facilitates simple control of the tightness of a cleat edge for accommodating interconnection of different gauge duct and fittings and the like.

It is another object to provide a cleat bending machine which readily bends all sizes of flat sheet and partial and fully formed duct and fittings.

It is another object to provide a cleat bending machine which readily accommodates raised seam locks in ducts and the like while forming cleats in the duct.

It is still another object to provide a hydraulic power system for a cleat bending machine which has a simple and highly effective mechanical control.

It is yet another object to provide a cleat bending machine which responds to encountering excessive bending stress, obstructions, and malfunctions and the like, by stopping operation without overstressing any components of the machine.

The foregoing and other objects are realized in accord with the present invention by providing a cleat bending machine which forms a simple cleat edge of the highest quality on fiat sheet, heavy assembled duct, or small fittings, with one hydraulically powered swing of its bending head. Mechanical actuation of the machine hydraulic power system initially effects bending of the sheet (for example) edge backwardly upon itself through a predetermined angle of less than 180, whereupon an inner bending blade which is cooperating in making the bend is automatically withdrawn. The head continues without hesitation, however, to complete the bend through an angle in excess of 180.

At somewhere in excess of 180 of bend, depending upon the setting of the cleat bending machine according to the present invention, the bending head stops its bending travel. The head then returns to its at rest position and, in doing so, releases the metal sheet and its newly formed cleat. The complete forming cycle, including bending travel and return travel of the bending head requires only about three seconds.

Bending force is provided by hydraulic power system. If the bending force required for a particular bend exceeds a predetermined safe limit, however, pressure buildup of the power system as a result of the excessive force required is vented to exhaust, assuring that the bending machine will not be subjected to excessive stress in any of its components. Similarly, if the bending head encounters resistance during return travel, fluid under pressure effecting return is vented to exhaust. The hydraulic power system is mechanically energized by the machine operator through a simple mechanical control.

The invention, both as to its organization and method of operation, taken with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanyy ing drawings, in which:

FIGURE 1 is a front perspective view of the bending machine embodying features of the present invention;

FIGURE 2 is an enlarged side elevational view of a cleat formed according to the present invention in the edge of a metal sheet;

FIGURE 3 is a top plan of the cleat bending machine, with parts broken away and other parts removed for clarity;

FIGURE 4 is a view taken along line 4-4 of FIG- URE 3;

FIGURE 5 is a sectional view taken through the bending head assembly of the machine and a portion of its supporting frame and bed assembly;

FIGURE 6 is another sectional view taken through the bending head assembly and a portion of the supporting frame and bed assembly, with parts broken away;

-FIGURE 7 is yet another sectional view taken through the bending head assembly and a portion of the supporting frame and bed assembly, with parts broken away;

FIGURE 8 is a sectional view of the head assembly and its supporting frame and bed assembly with the head assembly pivoted through approximately 164 during bending travel of the head assembly;

FIGURE 9 is a sectional view similar to FIGURE 8 with the bending head assembly shown at full travel, in excess of from its at rest position in the prese-nt i1- lustration;

FIGURE 10 is a somewhat diagrammatic illustration of the hydraulic powersystem in the machine;

FIGURE 1l is another somewhat diagrammatic illustration of the hydraulic power system; and

FIGURE 12 is a diagrammatic illustration, in section, of the conventional control valve in the hydraulic power system.

Referring now to the drawings, and particularly to FIGURE l, a cleat bending machine embodying features of the present invention is show-n generally at 10. The machine is adapted to receive the edge 11 of a sheet 12 (see FIGURE 2) or heating duct formed of galvanized iron or the like and bend a cleat 1.3 in the edge of the sheet in a single, continuous operation combining speed and economy with precision and uniformity. A cleat having a bend of in excess of 180 is readily formed by the machine 10. Furthermore, the degree of bend of the cleat 13 can be precisely adjusted to suit varying gauge sheet 12, for example.

The cleat bending machine 10 includes .a frame and bed assembly 15 upon which is mounted a bending head assembly 16. The bending head assembly 16 is pivotally mounted on the frame and bed assembly accordi-ng to the present invention and these assemblies are adapted to receive the edge 11 of a sheet 12, for example, and cooperate to bend a cleat 13 in the edge of the sheet with power supplied through a hydraulic actuator assem-bly 17. The hydraulic actuator assembly 17 drives the head assembly 16 through a complete cleat forming cycle at the instance of an operator who selectively energizes the hydraulic actuator assembly 17. According to the pres-ent invention, Ia complete cleat forming cycle requires approximately three seconds and the machine is again ready to receive a sheet 12 for the next cleat 13 bending operation.

The frame and bed assembly 15 includes a spaced pair of mounting stanchions 20. The stanchions 2t) are fabricated of heavy gauge steel or the like and include legs 21 welded to and extending upwardly from corresponding feet 22 which rest on level supporting surface. Extending between the legs 21 adjacent their front edges and secured to the legs by bolting or the like is a heavy steel angle member 23 welded to parallel end walls 27 (only one shown). The angle member 23 includes a long vertical leg 24 and `a short leg 25 extending rearwardly from its base. A smaller angle member 26 is welded in inverted relationship -on the back of the angle member 23 and extends between the end walls 27, being welded thereto also.

The bending head assembly 16 is, as has been pointed out, pivotally mounted on the frame and bed assembly 15. As illustrated in its at rest position in FIGURES 3 and 4, for example, the assemblies 16 includes a pair of substantially identical end plates 30 disposed parallel to each other and having pivot arms 31 extending forwardly therefrom. Each pivot arm 31 is pivotally connected to a pair of upstanding mounting brackets 32 secured by welding or the like to the front face 33 of the vertical leg 24 on the an-gle member 23. The pivot pins 34 extending between the upper ends of corresponding brackets 32 through suitably formed bearing apertures in the pivot arms 31 define the pivot and bending axis X of the head assembly 16.

Extending between the oppositely disposed end plates 30 of the bending head assembly `and welding thereto, are a pair of opposed angle members including `a lower angle member 40 and an upper, inverted angle member 41. The angle members 40 and 41 are co-extensively welded together as well as to the end plates 30. With the head assembly 16 in its at rest position, the lower free end 42 of the depending leg 43 on the angle member 41 rests against a series of spaced rubber bumpers 44 suitably secured to the back of the angle member 26 in the frame and bed assembly 15.

inclined lupwardly and forwardly from the free end 45 of the horizontal leg 46 on the upper angle member 41 is a spaced series of bending head ngers 47. The bending head fingers 47 extend in this spaced series between the opposite end plates 30. The lower end 48 of each nger 47 is formed complimentary with the free end 45 of the leg 46 so that it Iseats rmly on the leg. Each bending head nger 47 is inclined upwardly and forwardly past -bevelled upper edge 50 on the angle member leg 24 (with the head assembly 16 in its at rest position) to a flat horizontal platen surface 51 immediately below and adjacent the pivot axis X of the bending head assembly.

Each platen surface 51 is co-planar and aligned with a workpiece support bed defined by -llat support surfaces 52 fo-rmed on support fingers 53 bolted to a relieved area 54 of the front face 33 on the vertical leg 24 of the angle member 23 in the frame and bed assembly 15. A series of the fingers 53 are mounted along the length of the relieved area 54 to act as a bed for the sheet 11 or a duct section, for example, during the bending operation. These fingers 53 are intentionally made of yvarying width to facilitate the acceptance of depending side walls on duct sections (not shown) of varying width. To accommodate longitudinal roll formed `locks on the edges of a duct section, recessed areas 55 of varying size and arrangement are cut in one or both of opposite sides of the support surfaces 52 on the fingers 53, according to the present invention.

When the edge 11 of the sheet 12, for example, is inserted into the machine 10, it is placed on the support surfaces 52 of the fingers 53 and slid in underneath the forwardly extending lip 60 of a retractable bla-de 61 in the bending head assembly 16. In this position, the edge 11 will overlie the platen surfaces 51. The lower surface 63 of the lip 60 is spaced a predetermined slight distance from the platen surfaces 51 dependent upon the thickness of the sheet 11 to be handled by the machine 10.

The blade 61 is a generally dat steel element which extends between, and is inclined relative to, a pair of oppositely disposed end guide bars `66. The blade 61 is secured to each guide bar 66 by welding or the like and has a bevelled hat base 67 which extends below the guide bar 66 and rests loosely on top of the flat horizontal leg 46 of the angle member 41.

Extending perpendicularly down from the lower lip surface 63 of the blade 61 is a blade abutment surface 68. The abutment surface 68 engages an abutment surface 69 on the platen 47 adjacent the platen surface 51 when the head assembly 16 is in its at rest position, whereby a closed bottom slot is formed between the lip 60 and the platen surfaces 51 for receiving and positioning the edge 11 of the sheet 12. In the illustrations of FIGURES 3 and 5, however, the blade 61 is shown slightly retracted so that surfaces 68 and y69 are made clearly recognizable.

With the head assembly 16 in its at rest position, the blade 61 is resiliently urged forwardly in a horizontal plane toward the platen 47 by coil springs 75 seated in cylindrical bores 76 extending lengthwise through each of the guide bars 66. To this end, a guide block 77 slidable in each bore 76 urges a corresponding spring 75 against a bottom shoulder 78 in the bore. The guide block 77 in each bore 76 is pivotally connected at 81 to an inverted, U-shaped length S3 which enters the bore 76 through a longitudinally extending slot 84 in the upper surface of each of the guide bars 66. Each link 83 extends forwardly, over the pivot axis X of the bending head assembly 16, to a pivotal connection 86 with a bracket S7 mounted on the innermost bracket 32 in each pair of brackets 32 which pivotally mount the head assembly 16 on the frame and bed assembly 15. The length of each link 83 is such that each spring is slightly compressed with the head assembly 16 at rest and, accordingly, the blade 61 is lightly urged into engagement with the abutment surface 69 on the plate 47.

The machine 10 has been, to this point, described with the head assembly 16 in its at rest position. When the leading edge 11 of a sheet 12, for example, is slid on the finger support surfaces 52 between the blade lip 60 and the platen surface 51, into engagement with the abutment surface 68, energization of the hydraulic actuator assembly 17 by the operator initiates forward pivoting of the bending head assembly 16 about the axis X from its at rest position as seen in FIGURE 6, for example, toward its full travel position, as seen in FIGURE 9. That portion of the leading edge 11 on the sheet 12 which extends between the lip surface 63 and the platen surfaces 51 is, accordingly, bent forwardly about the axis X.

According to the present invention, after the head assembly 16 has pivoted through an arc of approximately 164 during bending travel from its at rest position to its full travel position, the blade 61 is automatically retracted to remove the lip 60 from engagement with the leading edge 11 on the sheet 12 while the head assembly 16 `continues its pivotal movement to an arc of in excess of During travel from 164 to 180 plus, the platen surfaces 51 continue to bend the edge 11 of the sheet 12 downwardly, with the sheet 12 supported on the finger support surfaces 52 to form the cleat 13.

Automatic retraction of the blade 61 at approximately 164 of travel through the 4bending portion of the cleat forming cycle is effected by spring loading the blade away from the platen 47 as the head assembly 16 pivots about its axis X toward its -full travel position. During this travel, the guide blocks 77 are moved away from corresponding springs in t-he bores 76 by the links S3 as they pivot about the pivotal axis 86, because of the forwardly displaced relationship of the pivotal connections 86 from the bending axis X. The guide block 77 thus releases all pressure urging the blade 61 toward the platen 47 after only a short distance of bending travel.

After approximately 45 of bending head assembly 16 travel about the axis X, the guide blocks 77 begin to compress corresponding coil springs 90' in each of the bores 76 opposite the guide blocks from coil springs 75. By the time the head assembly 16 has moved through an arc of approximately 164, substantial compressive force is stored in each of the coil springs 90; the springs 90 being retained in corresponding bores 76 by cross pins closing the outer ends of the bores. Until the head assembly has travelled to an arc of approximately 164 in its bending travel, however, it is prevented from retracting by a Ablade lock sub-assembly 92.

The blade lock sub-assembly 92 includes a roller 95 mounted for rotation on a pin 96 ydepending from the rear end 97 of each of the guide bars 66 which mount the retractable blade 61. With the head assembly 16 in its at rest position, and upwardly extending detent block 98 secured to each end of a release bar 99 slidable mounted on the ldepending leg 43 of the angle member 41 is positioned immediately behind a corresponding roller and, accordingly, prevents the blade 61 from moving rearwardly under the urging of the coil springs 90.

The release bar 99 is mounted for sliding movement on the leg 43 in a pair of U-shaped guide brackets 100 suitably bolted to the leg. A coil spring 101 suitably aiiixed to the bar at 102 and secured to the leg 43 at 103, urges the bar 99 toward the right in FIGURE 3 into an end stop position, as illustrated.

Aixed to the extending end of the release bar 99, is a cam block 111 having a cam surface 112 formed on its leading edge. As the bending head assembly 16 pivots about the axis X on the frame and bed assembly 15, and the coil springs 90 are compressed to build up spring force tending to retract the blade l61, the cam block 111 moves in an arc along the inner side wall 113 of the housing 114 for components of the actuator assembly 17 until t-he head assembly has pivoted through an arc of approximately 164. At this point in its arcuate travel, the cam surface 112 on the cam block 111 engages a cam roller suitably mounted on the side wall 113 in the path of travel of the cam block 111 and release bar 99 is forced toward the left in FIGURE 3 to move the detent blocks 98 from behind the rollers 95.

With the detent block 98 no longer resisting rearward movement of the blade 61, the coil springs 90 retract the blade 61 suddenly and forcefully, from the position seen in FIGURE 3 to the position seen in FIGURE 8. The blade 61 is driven rearwardly (actually forwardly with the bending head assembly pivoted through an arc of 164) with the lower surface 67 of the blade sliding on the horizontal leg 46 of the upper angle member 41 until the forward wall of a vertically extending, horizontally elongated slot 126 formed in each end of the blade 61 engages an upstanding stop member 127 bolted to the horizontal leg 46.

The blade 61 is guided in the sliding movement by the stop members 127 and a longitudinally spaced series of pins 128 extending up through corresponding, horizontally elongated slots 129 in the blade body; the pins 128 being mounted in the horizontal leg 46 of the angle member 41. An enlarged head 130 on each of the pins 128 prevents the blade from lifting olf of the horizontal leg 46 in its sliding movement since the head assembly is pivoted to a point where gravity would normally tend to cause the blade to fall away from the leg.

As the blade 61 retracts in the aforedescribed manner, the uniform ending travel of the head assembly 16 about the pivot axis X continues toward the full travel position illustrated in FIGURE 9. During the latter portion of this pivotal movement from 164 to 180 plus, the platen surface 51 continues to bend the cleat 13 into the sheet 12, friction preventing the sheet 12 from popping out from between the platen surface 51 and the upper supporting surface 52 on the support linger 53.

As the head assembly 16 passes through 180 of arcuate bending travel about its pivot axis X, the bevelled upper surface on the lip 60 of the retracted blade 61 engages the sheet 12 or the front corners 136 on the support fingers 53. Further travel of the head assembly 16 forces the lip 60 end of the blade 61 toward the horizontal leg 46 of the angle member 41, thus tilting the blade on the leading edge 137 of its base surface 67. This tilting accommodation of the blade 61 is necessary to complete a bend in excess of 180.

It is imperative, of course, that the blade 61 be tilted back to its normal position, with the lower surface 67 resting fiat on the horizontal leg 46, when the head assembly 16 begins its return travel to its at rest position. Otherwise the lip 60 of the blade 61 would engage the abutment surface 69 as the blade returned to the position illustrated in FIGURES 5-7. To this end, a spring biased lever arm 140 is pivotally mounted at 141 on the outer end plate 30 of the bending head assembly 16 and has one arm 142 extending in generally parallel relationship with the corresponding guide bar 66. A roller 143 mounted on the free end of the arm 142 overlies the upper surface 144 on the guide bar 66. The downwardly extending arm 145 of the lever arm 140 is biased in a counterclockwise direction in FIG-URE 4 by a spring 146 seated in a recessed block 147 mounted on the plate 30. It will thus be seen that the leverl arm 140, through the roller 143, constantly biases the rear end of the blade 61 toward engagement with the leg 46 of the angle member 41. It is this biasing effect which raises the lip 60 of the blade 61 for return to overlying relationship with the platen surface 51 when the head assembly 16 begins its return travel from the position illustrated in FIGURE 9 toward the position illustrated in FIGURES 4-7, for example.

The aforedescribed bending travel of the bending head assembly 16 is effected by force which the hydraulic actuator assembly 17 provides. As seen in FIGURES 10 and 11, the hydraulic actuator assembly 17 includes a conventional vane type rotary hydraulic actuator 150 and a conventional four-way, three position, valve 151 mounted in the housing 114 secured to one stanchion 20 of the frame and bed assembly 15. The actuator 150 and valve 151 are interconnected by a fluid conduit cornplex 153. Fluid under pressure is supplied to the actuator 150 through the valve 151 and the fluid conduit complex 153 from a conventional fluid pump unit 154 (shown only diagrammatically in FIGURE 1) via a supply conduit 155. It has been found that a pump having a 2500 p.s.i. capacity is sufficient to power the average machine 10, but it might be varied with machine 10 capacity, of course. Exhaust fluid is returned to the pumping unit 154 through an exhaust conduit 156.

The valve 151 is manipulated by an operator through a control unit to supply fluid under pressure to one inlet fitting 161 or the other 162 of the actuator 150 and drive its output shaft 163 in a counterclockwise or clockwise direction (as seen in FIGURE 11). The shaft 163 is operatively connected to the bending head assembly 16 in a manner hereinafter discussed in detail, and accordingly, pivots the head assembly 16 about its axis X through the aforedescribed bending travel of its cleat forming cycle in counterclockwise travel. After counter- :lockwise travel of the head assembly 16 through an arc of 180 plus to form a cleat 13, servo-mechanism 164 responsive to travel of the head assembly 16 and effective on the valve 151 reverses fluid flow to the actuator 150 to initiate clockwise or return movement of the head assembly 16 toward its at rest position.

The housing 114 is a box-like structure comprising the inner wall 113 bolted to the corresponding end wall 27 on the angle member 23, an outer wall 165, a front wall 166, back Wall 167, top 168, and bottom 169. Inside the housing 114 and extending between the inner and outer walls 113 and 165 is an actuator mounting plate 175 welded to the top 168. A pair of angle iron sections 176 welded along their free edges 177 to the back of the mounting plate 175 and at their ends to the inner wall 113, and outer wall 165, strengthen the mounting plate 175.

The conventional actuator 150 mounted on the front of the mounting plate 175 is preferably a Houdaille Hydroac rotary actuator of the single vane type. The actuator 150 used in this instance is the Tiny Model of the Hydroac which is capable of developing 2700 inchpounds of force at 3000 p.s.i.

The body 180 of the actuator 150 is generally cylindrical in shape and has a suitable base 181 formed unitary with the body. The base 181 of the body 180 is secured to the front surface of the mounting7 plate by conventional machine bolts 182. With the actuator 150 mounted in this relationship, the output shaft 163 extends parallel to the axis X of pivoting of the head assembly 16 through an aperture 183 in the inner wall 113 of the housing 114. The free end of the output shaft 163 is splined in a wellknown manner and mounts a torque disc 185 for rotation with the shaft. The torque disc 185 protrudes through the aperture 183 in the wall 113 into immediately adjacent relationship with the corresponding end plate 30 of the bending head assembly 16.

A drive adaptor block 190 is mounted on the periphery of the torque disc 185 by welding or the like and has a pin receiving slot 191 formed therein in radial relationship with the disc. Secured to the corresponding end of plate 30 of the bending head assembly 16 in suitable position for receipt in the slot 191 is a drive pin 192. It will thus be seen that rotation of the torque disc 185 by the actuator 150 is effective to pivot the bending head assembly 16 about its axis X between the at rest and full travel positions of the head assembly.

The conventional three-position valve 151 which directs fluid flow to drive the actuator shaft 163 in one direction or the other comprises a vertically disposed valve body 200 aflixed to the inner wall 113 of the housing 114 by L-brackets 201 and suitable screws 202. The valve body 200 has a valve bore 203 formed therein and a valve spool 204 slidable in the bore between a full-up position and a full down position through a neutral position.

In the neutral position illustrated in FIGURE l1, fluid entering the valve body 200 from the inlet port 210 through the supply conduit 155 passes around the two valve spool lands 211 to the exhaust port 212 and out through the exhaust fitting 213 and conduit 156. Accordingly, the valve 151 is not effective to direct fluid under pressure to either inlet fitting 161 or 162 of the actuator 150. As will hereinafter be discussed in the operation of the machine 10, the valve spool 204 is in its neutral position only at full travel of the bending head assembly 16, however, and then only momentarily.

With the bending head assembly 16 in at rest position, the valve spool 204 is normally in full up position wherein fluid under pressure from the supply conduit 155 is directed from the inlet port 210 in the valve body 200 to its upper cylinder port 215. The upper cylinder port 215 is connected to the center section 216 of a three-section, L-shaped fitting 217, by a fluid conduit 218. The foot section 219 of the fitting 217 is, in turn, connected to the 8 actuator inlet fitting 161 so that with the valve spool 204 in full up position, fluid under pressure is effective in the actuator 150 to urge the shaft 163 in a clockwise direction and, accordingly, hold the head assembly 16 in at rest position.

An effective pressure of approximately p.s.i. is all that is desired for urging the head assembly 16 toward its at rest position. Accordingly, a convention pressure relief valve (not shown) is positioned inside the upper leg section 220 of the fitting 217, and the leg section 220 is connected by a by-pass conduit 221 to the exhaust conduit 156 through an exhaust fitting 213.

With the relief valve in the tting 220 set at 100 p.s.i. while the pumping unit 154 continuously delivers fluid to the valve 151 through the supply conduit 155, it will be recognized that this fluid is by-passed back to the exhaust conduit 156 through the relief valve and the conduit 221 when the head assembly 16 is in at rest position, this at rest position being maintained by the 100 p.s.i. force. At the same time, the opposite side of the actuator is vented to exhaust from the other inlet fitting 162 through the conduit 225, a conventional metering valve fitting 226 and the cylinder port 227 in the valve 151 to the exhaust port 212 therein. The exhaust port 212 is connected to the exhaust conduit 156 through the fitting 213, as has been pointed out, The significance of the metering valve fitting 26 will be discussed in detail in the succeeding description of the remainder of the hydraulic system.

The valve core 204 is stopped in its full up position by a lever 228. The lever 228 extends through an aperture in the inner wall 113 of the housing 114 and is pivotally mounted on a pin 231 secured to the wall 113. A coil spring 232 disposed between the inner end 233 of the lever 228 and an extension 234 of the valve body bracket 201 biases the lever upwardly into its full up position. Another coil spring 205 encircling the protruding valve spool head 206 biases the valve core 204 up against the lever 228.

To initiate forward movement of the bending head assembly 16 in the bending travel portion of the cleat forming cycle, the operator manipulates the control unit 160 to move the valve spool 204 downwardly against the bias of the spring 205. This is accomplished by the wire 235 of a Bowden cable 236 which extends through a fitting 237 in the bottom 169 of the housing 114 and an aperture (not shown) in the extension 234 of the bracket 201 (through the coil spring 232) to a pivotal connection with the inner end 233 of the lever 228. The cable 235 extends to a foot pedal assembly 238 where the free end 239 of the wire 235 is connected to a transversely extending shatf 240 longitudinally slidable in a pair of horizontal slots 241 formed in spaced flanges 242 on the base 243 of the foot pedal assembly 238.

A foot plate 250 in the `foot pedal assembly 238 has the outer ends 251 of its depending legs 252 slidably seated on the base 243 and its inner end 253, through the medium of a transversely mounted roller 254 extending between the sides 252, adapted for rolling movement on an inclined plate 255. Pressure of the operators foot on the foot plate 250 thus causes the roller 254 to ride down the inclined plate 255 and force the shaft 240 rearwardly in the slots 241, drawing the wire 235 through the Bowden cable 236 and pulling the lever 228 downwardly against the bias of the springs 232 and 205. The valve spool 204 is thus moved to its full down position. When the valve spool 204 is moved to its full down position, fluid at whatever pressure is required to form the cleat up to rated capacity of the machine enters the inlet port 210 in the valve body 200 and is directed out of they cylinder port 227 through the metering valve fitting 226 and the conduit 225 to the inlet fitting 162 of the actuator 150. The actuator 150 immediately responds to start rotating the bending head assembly 16 about the axis X in a counterclockwise direction to form a cleat 13 in the edge 11 of a sheet 12 of galvanized iron, for example.

The operator continues to hold his foot down on the foot plate 250 and the actuator 150 continues to pivot the bending head assembly 16 Iforwardly about the axis X in forming the cleat 13. At approximately 164 of arcuate travel, the blade 61 is retracted in the manner hereinbefore discussed in detail while the head assembly 16 continues its pivotal movement in forming the cleat 13. When the head assembly 13 passes through the prescribed arc, approximately 193 in the present illustration, the servo mechanism 164 neutralizes the valve spool 204 and all fluid pressure forces on the actuator 150 are instantaneously cut E. Should the bending head assembly 16 jam or otherwise run into great resistance in its bending travel, a by-pass valve (not shown) in the pump unit 154 bypasses uid under pressure and no damage to the machine results.

The servo mechanism 164 which neutralizes the valve spool 204 at full travel of the bending head assembly 16 comprises a mounting block 270 secured across a corresponding pair of the brackets 32 which support the bending head assembly for pivotal movement about the axis X. A vertically disposed passage 271 is formed in the block 270 and a pin 272 is freely slidable in the passage 271. The lower end 273 of the pin 272 rests on the head 274 of a vertically adjustable screw 275 threaded into a suitably formed aperture in the outer end of the lever 228. A lock nut is provided on the screw 275 to fix the vertical position of its head 274.

After the head assembly 16 has pivoted through a predetermined arc, 193 in the illustration, the pivot arm 31 on the corresponding side plate forces the pin 272 downwardly, causing the lever 228 to move counterclockwise and permit the valve spool 204 to move toward its neutral position. By adjustment of the height of the head 274 on the screw 275, it will be seen that neutralization of the valve spool 204 can be accomplished at any predetermined degree of arcuate travel of the bending head assembly 16. Raising the head 274 of the screw 275 and resetting the lock nut would cause neutralization to occur sooner, for instance at 185. In this manner the gauge of thesheet 12 or duct (not shown) being bent can be ac commodated by adjusting the tightness of the cleat 13.

Regardless of the setting of the servo mechanism 164, however, co-incident with its neutralizing the valve spool 204 at a predetermined full travel position of the head assembly 16, the operator releases the foot plate 250 and the coil springs 232 and 235 and urges the lever 228 and valve spool 204 upwardly to full up position of the spool once more. The valve 151 again directs fluid under pressure to the inlet fitting 161 of the actuator 150 (at approximately 100 p.s.i. because of the relief valve in the fitting 220) while fluid is evacuated from the opposite side of the actuator motor 150 through the actuator inlet fitting 162.

The actuator 150 turns the shaft 163 and the bending head assembly 16 in a clockwise direction, returning it to its at rest position. The rate of return is controlled by adjusting the flow metering valve fitting 226 in a `well-known manner. As the bending head assembly reaches approximately 90 of arcuate return travel, the blade 61 is returned by the force of gravity to its operative position, as illustrated in FIGURES 6 and 7, for example. When the bending head assembly 16 reaches at rest position, fluid under pressure is bypassed back to the exhaust conduit 156 again through the relief valve (not shown) in the fitting 220 and manner hereinbefore discussed in detail, and the machine is ready to form a cleat 13 in another sheet 12 or duct or the like.

One other feature of the present invention merits consideration. This is the head assembly balance arrangement 280 which produces a continuously increasing counter balance force effective on the heavy bending head assembly 16 as it pivots past 90 arcuate travel during bending travel so that at full travel it does not require an excessive torque to initiate return travel of the assembly. The balance assembly 280 includes a mounting element 281 welded to the inner face 282 of the torque disc 185. A piece of roller chain 283 is pivotally connected to the lower end 284 of the element 281 and. extends downwardly through a guide aperture 285 in a horizontally extending bracket 286 welded to the motor mounting plate 175. The chain 283 is connected to and supports a freely depending rod 287 below the extension 286. The rod 287 has a stop nut 288 secured to its lower end and a coil spring 289 encircles the rod and extends between the stop nut 288 and the bracket 286.

Referring again to the bending travel of the bending head assembly 16, the roller chain 283 begins to draw up through the aperture 285 and compress the coil spring 289 as the torque disc 185 begins to pivot the bending head assembly 16 through bending travel. The further the bending head assembly 16 pivots, the more spring 289 is compressed. After the bending head assembly 16 has turned through approximately 90, a pick-up element 290, also welded to the inner face 282 of the torque disc 185 picks up the roller chain 283, thus maintaining a relatively constant torque arm and counter torque on the bending head assembly 16.

The strength of the coil spring 289 is precalculated to provide a balance for the bending head assembly 16 once it has moved through full travel in the present illustration. The stop nut 288 on the bottom of the rod 287 is adjustable, however, to adjust the balance point of the balance assembly 280 for any prescribed full travel.

It will now be recognized that a machine 10 has been described which bends sheet and duct edges and the like quickly and uniformly. The machine 10 has been illustrated and described as bending on a horizontal axis X, but it might be set up to bend on a vertical axis also, or oriented otherwise.

While the embodiment described herein is at present considered to be preferred, it is understood that various modifications and improvements may be made therein, and it is intended to cover in the appended claims all such modifications and improvements as fall within the true spirit and scope of the invention.

What is desired to be claimed and secured by Letters Patent of the United States is:

1. A machine for bending a cleat in the edge of a sheet member, comprising: bed means, a bending head assembly mounted on said lbed means for pivotal movement about a bending axis, power means connected to said head assembly for pivoting said assembly about said axis, support surface means on said bed means for supporting the sheet member with its edge extending into operative relationship with said bending head assembly, platen means fixed on said head assembly for underlying the edge of the sheet member, blade means movably mounted on said head assembly for movement between a first position in which said blade means overlies the sheet member edge and a second position wherein said blade `means is retracted from said sheet member edge, and means for moving said blade means from said first position to said second position when the platen means has pivoted through a predetermined arc of less than degrees in bending travel, said platen means being movable through a -continuing arc in excess of 180 degrees whereby a cleat with a bend in excess of 180 degrees is formed in the sheet member edge without interference by said blade means.

2. A machine for bending a cleat in the edge of a sheet member, comprising: bed means, bending head means mounted on said bed means for pivotal movement between an at rest position and a full travel position, means connected to said head means for pivoting said head means between said positions, said bending head means including platen means for supporting the edge of the sheet member and blade means for overlying the edge, and means for withdrawing said blade means from overlying relationship with the sheet member edge when said platen means has pivoted through a predetermined arc of less than 180 degrees in bending movement from said at rest position to said full travel position, said platen means being movable to said full travel position through a continuing arc in excess of 180 degrees to form a cleat with a bend in excess of 180 degrees in the sheet member edge without interference by said blade means.

3. The machine of claim 2 further characterized in that said pivoting means comprising hydraulic power means drivingly connected to said bending head means, said power means driving said bending head means through an arc of in excess of 18() degrees from said at rest position to said full travel position in one continuous movement.

4. A machine for bending a cleat in the edge of a sheet member, comprising: bed means, bending head means mounted on said bed means for pivotal movement about a bending axis between an at rest position and a full travel position, means connected to said head means for pivoting said head means about said axis, support means on said bed means for supporting the member with its edge extending into operative relationship with said bending head means, said bending head means including head structure, platen means fixed on said head structure for underlying the edge of the sheet member, blade means movably mounted on said head structure for movement between a first position overlying the sheet member edge and a second position retracted from the sheet member edge, means tending to urge said blade means toward said second position during pivotal movement of said head means toward said full travel position, and means retaining said blade means in said first position during said travel toward said full travel position until said platen means has pivoted through a predetermined arc of less than 180 degrees whereupon said blade means moves to said second position, said platen means being movable to said full travel position through a continuing arc in excess of 180 degrees, whereby a cleat with a bend in excess of 180 degrees is formed in the edge without interference by said blade means.

5. The machine of claim 4 further characterized in that said retaining means comprises a release bar movably mounted on said head structure, cam means on said release bar, and cam actuator means positioned for engagement by said cam means when said bending head means has pivoted through said predetermined arc of less than 180y degrees, whereby said release bar is moved to release said blade means and permit said urging means to move said blade means toward said second position.

6. The machine of claim 4 further characterized in that said blade means is angularly tiltable on said head structure for tilting to accommodate pivoting movement of said bending head means into said full travel position.

7. The machine of claim 6 further characterized by and including biasing means for urging said blade means out of said tilted relationship when said bending head means is returned from said full travel position toward said at rest position.

8. A machine for bending a cleat in the edge of a sheet member, comprising: bed means, bending head means mounted on said bed means for pivotal movement about a bending axis through an arc in excess of 180 degrees between an at rest position and a full travel position, support surface means on said bed means for supporting the sheet member with its edge extending into operative relationship with said head means, and power means connected to said head means for pivoting said head means through a cleat bending cycle including bending travel from said at rest position to said full travel position and return travel to said at rest position, said power means including a uid actuator operatively connected to said bending head means, a source of fluid under pressure for driving said actuator, and valve means for directing fluid under pressure to one side of said actuator whereby said bending head means is urged toward said at rest position,

or to the other side of said actuator whereby said bending head means is urged toward said full travel position.

9. The machine of claim 8 further characterized by and including means for normally urging said Valve means into a position whereby fluid under pressure is directed to said actuator to urge said bending head means toward said at rest position.

10. The machine of claim 8 further characterized in that said valve means comprises a three-position valve including a one position wherein fluid under pressure is directed to said actuator to urge said bending head means toward said at rest position, a two position wherein fluid under pressure is directed to said actuator to urge said bending head means toward said travel position, and a neutral position wherein no uid under pressure is directed to said actuator and means normally urging said valve means into said first position.

111. The machine of claim 10 further characterized by and including operator means for moving said valve into said two position to deliver uid under pressure to said motor means for turning said bending head means from said at rest position to said full travel position to form a cleat in the edge of the sheet member.

12. The machine of claim 11 further characterized by and including a servo-means responsive to said bending head means for moving said valve to said neutral position when said bending head means has moved in bending travel from said at rest position to said full travel position.

13. A machine for bending a cleat in the edge of a sheet member, comp-rising: bed means, bending head means mounted on said bed means for pivotal movement about a bending axis through an arc in excess of degrees between an at rest position and a full travel position, support surface means for supporting the sheet member with its edge extending into operative relationship with said bending head means, and power means connected to said head means for pivoting said head means through a cleat bending cycle including bending travel from said at rest position to said full travel position and return travel to said at rest position, said power means including a rotary hydraulic actuator having an output shaft operatively connected to said bending head means for pivoting said bending head means through said bending head travel in one direction and through said return travel in the opposite direction, a source of fluid under pressure, and valve means for directing fiuid under pressure from said source to one side of said actuator for pivoting said head means toward said at rest position or to the other side of said actuator for pivoting said bending head means toward said full travel position, said valve means normally directing fluid under pressure to said one side of said actuator.

14. The machine of claim 13 further characterized by and including operator means for manipulating said valve means to direct fluid under pressure to the other side of said actuator for initiating bending travel of said bending head means from said at rest position to said full travel position to form a cleat having a bend in excess of 180 degrees in said sheet member edge.

15. The machine of claim -14 further characterized by and including servo-means responsive to said bending head means reaching its full travel position to manipulate said valve means for relieving all uid pressure on said rotary hydraulic actuator whereby bending travel of said bending head means is terminated.

16. The machine of claim 15 further characterized in that said servo-means includes adjustable means for adjusting the degree of arcuate travel of said head means before said iiuid pressure is relieved.

17. The machine of claim 2 further characterized by and including resilient means counter-balancing said bending head means during at least a portion of its travel from said at rest position to said full travel position, said resilient means introducing a progressively greater counter-balance force to said bending head means as it approaches its full travel position so that said head means is substantially balanced when in its full travel position.

18. The machine of claim 2 further characterized by and including support surface means on said ybed means :for supporting the sheet member in operative relationship with said bending head, said support surface means having a recess formed therein for receiving a seam lock in the sheet member with the sheet member ush against said surface means.

19. The machine of claim 18 further characterized in that said support surface means includes a support surface formed on a support finger, said recess means including a notch formed in said surface for receiving the seam lock.

20. The machine of claim 19 further characterized in support surfaces formed on a plurality of support ngers, and notches formed in a plurality of said ngers for receiving the seam lock.

References Cited UNITED STATES PATENTS 93,194 8/1869 Grim 72-310 377,336 1/1888 Stasch 72-310 422,944 3/ 1890 Hyndman 72-388 562, 877 6/ 1896 Wittebolle 72-310 1,506,096 8/ 1924 Stidworthy 72-388 CHARLES W. LANHAM, Primary Examiner.

that said support surface means includes a plurality -of 15 L. A. LARSON,Assstant Examiner, 

1. A MACHINE FOR BENDING A CLEAT IN THE EDGE OF A SHEET MEMBER, COMPRISING: BED MEANS, A BENDING HEAD ASSEMBLY MOUNTED ON SAID BED MEANS FOR PIVOTAL MOVEMENT ABOUT A BENDING AXIS, POWER MEANS CONNECTED TO SAID HEAD ASSEMBLY FOR PIVOTING SAID ASSEMBLY ABOUT SAID AXIS, SUPPORT SURFACE MEANS ON SAID BED MEANS FOR SUPPORTING THE SHEET MEMBER WITH ITS EDGE EXTENDING INTO OPERATIVE RELATIONSHIP WITH SAID BENDING HEAD ASSEMBLY, PLATEN MEANS FIXED ON SAID HEAD ASSEMBLY FOR UNDERLYING THE EDGE OF THE SHEET MEMBER, BLADE MEANS MOVABLY MOUNTED ON SAID HEAD ASSEMBLY FOR MOVEMENT BETWEEN A FIRST POSITION IN WHICH SAID BLADE MEANS OVERLIES THE SHEET MEMBER EDGE AND A SECOND POSITION WHEREIN SAID BLADE MEANS IS RETRACTED FROM SAID SHEET MEMBER EDGE, AND MEANS FOR 